This invention relates to atomic emission spectrometry and particularly to a system adapted for on-line analysis using atomic spectrometry.
Various analytical instrumentations have been developed and suggested for analyzing of solids and liquids. Generally, prior art systems of atomic emission spectrometry require an input of energy for the conversion of the material into a gaseous state. A detailed discussion of the prior art appear in Spectrochemical Analysis Published by Prentice Hall and particularly Chapter 9, "Arc and Spark Emission Spectrometry". The materials to be analyzed are in the form of solids or solutions in which the elements being monitored are bonded to other elements. In order to provide for atomic spectrometry analysis, the individual bond must be broken. The atomic elements will emit light in the ultraviolet visible, or near infrared spectral region in response to an appropriate input energy to the element. In addition, each element response is a particular unique element-related frequency. Generally, the input energy has been applied through a plurality of well known different energy sources including 1) flame; 2) electrothermal through the use of a graphite furnace; 3) electric arc; 4) electric sparks and 5) inductively coupled plasma using a radio frequency field. In all instances, the product is converted to a gaseous or plasma condition and the converted gas or plasma is exposed and directly analyzed on a sample-by-sample basis. Each gas or plasma sample is analyzed through light absorption or emission analyses. With atomic absorption, the system measures the light absorbed in the energized atom cell. In atomic emission processes, the light emitted from the energized atom cell is monitored. In atomic fluorescent procedures, the fluorescent light emitted from the energized atom cell is monitored.
For example, U.S. Pat. No. 4,238,198 which issued Dec. 9, 1980 discloses a system for analyzing liquid samples for total inorganic sulfur. The patented system takes a sample of the material and converts it to a volatile H.sub.2 S sample which is carried into a plasma chamber using a suitably inert gas. The emitted light of the evolved H.sub.2 S is analyzed to determine the total inorganic sulfur concentration within the sample.
Although such methods have been used for atomic emission analysis, the prior art has been significantly limited by the use of sampling procedures including the necessity of converting each sample to a gaseous state and then analyzing of the gaseous product in a separate analysis unit. There is a significant demand for a more direct method for elemental analysis of a liquid solutions, and particularly with a continuous or on-line procedure which eliminates the requirement for sampling.